1. Field of the Invention
The present invention relates to doors for animal enclosures and other enclosures and is more specifically directed to an improved door assembly for pivotally connecting a door to an enclosure in a manner that more evenly distributes the load of the door, reduces the potential for sagging and allows for removal and reattachment of the door with greater ease.
2. Description of Related Art
Animal cages, pens, kennels, runs, and other types of enclosures are generally accessed and closed by pivoting doors secured to the side of the opening in the enclosure via hinges that allow the door to be moved between open and closed positions. Various configurations of hinges are known, with the most common type being an interlocking leaf type comprising two separate leaf pieces attached with a hinge pin. The first leaf, for attachment to a frame or other portion of the enclosure, has a series of protruding barrel segments, with the second leaf, for attachment to a door, having corresponding offset barrel segments. The offset barrel segments of the first and second leaves are interlocked, with a separate hinge pin inserted into the barrel formed by the aligned barrel segments to join the two leaves. The door is thus attached to the frame or other portion of the enclosure, and can pivot between open and closed positions.
While known hinges do provide for supporting and pivoting a door, they also have numerous drawbacks. With the interlocked leaf configuration, the door leaf moves with respect to the frame leaf, pivoting around the inserted hinge pin. Thus, smooth operation of the hinge is hindered by the fact that the edges of the barrel segments of the door leaf engage the edges of the barrel segments of the interlocked frame hinge. This contact between the door leaf and frame leaf may interfere with operation of the hinge and can result in unwanted noise. Furthermore, in such a configuration, the weight of the door on the barrel segments translates to a twisting moment on the barrel segments of the leaves. This continuous twisting moment may even twist the barrel segments themselves, allowing the door to sag. While this sagging can be somewhat alleviated by providing larger hinges with more barrel segments, or more commonly, by using several hinges on a single door to distribute the weight of the door between the hinges, the problem is not fully eliminated. Over time and continued use, the hinge connection weakens and the door begins to sag and become more difficult to close.
Removal and reattachment of traditionally hinged doors can be difficult. In removing such a door, separate tools are often needed to extract the hinge pin. This can be especially difficult as the hinge pin is often stuck within the barrel segments of the hinge leaf. Reattaching the door can also be challenging because the individual barrel segments on each hinge leaf must be perfectly aligned for receipt of the hinge pin. Even when new, this can be a tricky process due to a door's size, shape and weight. In addition, when doors, frames, or hinge leafs are warped, damaged or out of square, reattachment can be nearly impossible.
Thus, it can be seen that there remains a need in the art for a pivoting door structure with enhanced load distribution to reduce sagging and that provides for a smoother, quieter operation and easier removal and reattachment.